OUTLINE: This is a randomized, multicenter study. Patients are stratified according to time from last prior chemotherapy (less than 6 months vs 6 months or more) and number of prior chemotherapy regimens (1 vs 2). Patients are randomized to one of two treatment arms. Arm I: Patients receive lurtotecan liposome IV over 30 minutes on days 1-3. Arm II: Patients receive lurtotecan liposome IV over 30 minutes on days 1 and 8. Courses repeat every 3 weeks in the absence of disease progression or unacceptable toxicity. Patients achieving complete response (CR) receive 2 additional courses after documented CR. Patients achieving partial response (PR) receive 4 additional courses after documented PR or until disease progression at investigator's discretion. Patients with stable disease continue therapy for a maximum of 6 courses. Patients are followed at 4 weeks and then every 3 months until disease relapse or progression.